Abstract: The inventive image recording apparatus records unit images with different combinations of light beams among a plurality of light beams emissive from a recording head when preparing the respective ones of C, M, Y and K plates. Also when the plurality of light beams are dispersed in quantity of light, therefore, density distributions of different tendencies result in the unit images recorded on the respective ones of the C, M, Y and K plates. In a resultant image formed by superposing the unit images with each other, therefore, fluctuation of densities can be canceled and reduced.

Abstract: A light source which is a surface emitting laser including a plurality of apertures that correspond to light emitting regions arranged in a two-dimensional array and limit the regions, and a scanning optical system satisfies conditions of Dm·|?m|<?m and Ds·|?s|<?s, where Dm is a width of each of the apertures in a main scanning direction, Ds is a width of the each aperture in a sub-scanning direction, ?m is a magnification of both of a coupling optical system and the scanning optical system in the main scanning direction, ?s is a magnification of both of the coupling optical system and the scanning optical system in the sub-scanning direction, ?m is a size of an optical spot in the main scanning direction formed on a scan target surface, and ?s is the size of the optical spot in the sub-scanning direction formed on the scan target surface.

Abstract: An image signal with an overshoot is generated on a positive-going edge of an input image signal with an overshoot producing unit. Then, a light signal with an overshoot is outputted from a recording light source in response to the image signal with the overshoot supplied from the overshoot producing unit. The light signal outputted from the recording light source is applied to scan a photosensitive medium to record an area gradation image on the photosensitive medium.

Abstract: A direct write holographic printer for producing RGB color reflection holograms is disclosed. A Nd:YLF crystal (1) in a laser cavity is excited to produce an emission at 1313 nm which is frequency converted by doubling to 656.5 nm and by tripling to 437.7 nm. In a separate cavity a similar Nd:YLF crystal (1a) is synchronously or asynchronously excited to produce an emission at 1047.1 nm (or at the related line of 1053 nm) which is frequency converted by doubling to 523.6 nm (or 526.5 nm). The emissions at 437.7 nm and 656.5 nm are combined co-linearly with the emission at 523.6 nm (or 526.5 nm) to produce a single RGB pulsed laser beam.

Abstract: A scanning optical apparatus having stable optical performance even if the characteristic of a vertical cavity surface emitting laser is fluctuated due to increase in drive current, and an image forming apparatus using the same are provided. The scanning optical apparatus comprises a converting optical system for converting a beam from the light source means having plural emission points into a beam of another state, deflecting means, and an imaging optical system for directing the deflected beam onto a scanning surface, and either pair of conditions is satisfied, 3?Fnos<Fnom?15 and d?s/dT<d?m/dT, or 3?Fnom<Fnos?15 and d?m/dT<d?s/dT, where Fnom and Fnos represent F numbers of the light source means side of the converting optical system in main and sub-scanning directions, ?m and ?s half value angles of far field pattern in the main and sub-scanning directions, and d?m/dT and d?s/dT the fluctuations of ?m and ?s due to temperature change.

Abstract: Disclosed is an optical scanning system and an image forming apparatus using the same, which is designed to reduce the overall size of the system and to make uniform the light spot diameter in a sub-scan direction, inside an effective scan region, as well as to ensure high-speed production of high-quality images, wherein the optical scanning system includes a light source, a condensing optical system, a deflector and an imaging optical system having one or more optical elements, wherein, in at least one optical element of the optical elements, the curvature of the opposite surfaces thereof changes continuously, inside an effective region, from the optical axis toward the peripheral portion thereof so that the sign of the curvature is reversed at the middle, and wherein, when the curvature radius of the surface of that optical element facing the deflector side, at the optical axis and in the sub-scan sectional plane, is denoted by rl0 while the least quantity of an absolute value of the curvature radius of the

Abstract: A light scanning apparatus capable of printing with a high quality and an image forming apparatus using the same are obtained. The light scanning apparatus is provided with an incidence optical system for guiding a light beam emitted from a light source part to a deflection part; an imaging optical system provided with a diffracting surface having a power at least in a sub-scanning section that guides the light beam deflected by the deflection part on a surface to be scanned; and a surface inclination correction function, in which a principal ray of the light beam is always positioned outside of a main scanning section during scanning. In the light scanning apparatus, each element is set so as to satisfy each conditional expression.

Abstract: The present invention discloses a serially connected LED lamps control circuit device, which is applicable for an integrated circuit and has the following three features: using a buffer circuit to increase the DATA and Clock lines to extend the distance between a plurality of serially connected devices, delaying half cycle of the timing of the DATA line to enhance overall system stability, and adding an internal latch signal generate circuit to simplify the requirements for external connections.

Abstract: An optical scanning device has an incident optical system that makes a light beam emitted from a light source unit enter to a deflection surface of an optical deflector in a state in which the light beam has a larger width than a width of the deflection surface in a main scanning direction, and an imaging optical system that images the light beam reflectively deflected by the optical deflector onto a surface to be scanned. In the device, a slit member that restricts a diameter of the light beam in a sub-scanning direction is provided within an optical path between the optical deflector and the surface to be scanned. A peak intensity of a spot of the light beam scanned on the surface to be scanned is made constant, or substantially constant across an entire effective scanning region.

Abstract: In an optical scanning apparatus, a light beam emitted from a light source is deflected and scanned by a light deflecting member, and then scanned and imaged with substantial speed uniformity onto a medium to be scanned by a scanning optical element. The apparatus is configured so that, when the angle formed by the light beam that is deflected and scanned and the optical axis of the scanning optical element is ?, the amount of positional deviation due to deviation from speed uniformity of the light beam on the medium to be scanned is ?(?), the spatial scan density on the medium to be scanned is P, and the maximum of an absolute value of the angle ? is ?o, an expression of |d?(?)/d?|?5.0×10/P?o holds.

Abstract: A printer CPU controls rotations of a photosensitive drum for black and photosensitive drums for other colors such that a phase angle difference between the photosensitive drum for black and the photosensitive drums for the other colors during image formation in a color mode is unchanged before and after execution of a black mode.

Abstract: A multi-beam scanning device includes a multi-beam light source unit that emits a plurality of light beams having different wavelengths. The light beams are aligned in a main scanning direction. The device further includes first polygonal mirror that deflects the plurality of light beams in the main scanning direction, an f? optical system, a second polygonal mirror that deflects the plurality of light beams passed through the f? optical system in an auxiliary scanning direction that is perpendicular to the main scanning direction, the second polygonal mirror deflects the plurality of light beams in the auxiliary direction by one line at each main scanning of the plurality of light beams, and a projecting optical system that projects the plurality of light beams deflected by the second polygonal mirror on a screen.

Abstract: This invention provides an optical scanning apparatus in which the degree of sensitivity of the bending of a scanning line on a surface to be scanned resulting from the disposition error of a scanning optical system is reduced, whereby good images can always be obtained, and an image forming apparatus using the same. The optical scanning apparatus has deflecting means for deflecting a beam emitted from light source means, and a scanning optical system having a plurality of scanning lenses for directing the beam onto the surface to be scanned, and a first scanning lens La is such that the shape thereof in a main scanning cross section is a meniscus shape having positive refractive power, and satisfies the condition that d1/fm<0.06, where fm is the focal length of the scanning optical system in the main scanning cross section, and d1 is the central thickness of the first scanning lens, and a second scanning lens is such that.

Abstract: Provided is an optical scanning apparatus for optically scanning a surface to be scanned, including: a light source unit that emits a beam modulated according to an image signal; a condenser lens for temporarily focusing the beam emitted from the light source unit into an image in a sub-scanning section in the vicinity of a deflection surface of a light deflector; and a scanning optical system for guiding the beam deflected by the light deflector onto the surface to be scanned, in which: in the sub-scanning section, the beam from the condenser lens is incident at an angle with a normal to the deflection surface; and an scanning optical element constituting the scanning optical system has an optical axis eccentric toward a deflection point side of the deflection surface with respect to a transmission position of a principle ray of the beam in a sub scanning direction.

Abstract: In an optical scanning apparatus having a light source, an incidence optical system for causing a beam emitted from the light source to be incident on a deflector, an imaging optical system for causing the beam reflected and deflected by the deflector to be imaged on a surface to be scanned, and a reflecting portion having a plurality of substantially plane reflecting mirrors disposed in an optical path between the deflector and the surface to be scanned, the reflecting portion includes a reflecting mirror of which the refractive power in a main scanning cross section is of an opposite sign. Provided are an optical scanning apparatus which does not involve structure and work for adjustment, and can obtain stable imaging performance by a simple method even if a plurality of mirrors are disposed, and an image forming apparatus using the same.

Abstract: A method for correcting defects (300) in an imaging system (10) that comprises several steps. Transmitting a digital image (370) to at least one spatial light modulator and capturing the resulting image. Comparing variation in intensity between each image pixel and at least one reference image pixel and deriving a correction factor (305) from the comparison. Determining gain of correction (480) at each code value (460) for each image pixel and applying the correction factor (580) and gain to the digital image (510).

Abstract: An optical printing device for exposing a photosensitive recording medium to form a grayscale image includes a print head having n rows of recording elements capable of exposure of different colors and aligned in a direction of advancement of the photosensitive recording medium, where n is an integer more than 1, the n rows of recording elements being spaced substantially a multiple of L×(m+k/n) apart in the direction of advancement of the photosensitive recording medium, where L denotes a distance between the centers of recording pixels according to the desired resolution of a recorded image, m is an integer of 1 or more, and k is an integer of 1 or more and less than n. The optical printing device also includes a head driver for driving the print head. Light from the print head is selectively exposed on the photosensitive recording medium to form the grayscale image.

Abstract: An optical scanning apparatus includes light sources, an aperture having, and coupling lenses. Numbers of the light sources and the coupling lenses are equal to each other and the apparatus satisfies an inequality 12.7 <(D×?0×m0×xdpi)/(2×NA) <38.1 and an equation ?0=(?+???)/(n?1), wherein D represents a width of the slit of the aperture, ?0represents a beam open angle, mo represents a total lateral magnification ratio, dpi represents a number of dots per inch, NA represents a numerical aperture, ?+ represents a positive open angle, ?? represents a negative open angle, and n represents the number. Further, an image forming apparatus using this optical scanning apparatus and an image forming method are provided.

Abstract: In this invention, the relationship between the attachment position of a sensor and the formation positional shift of a color image is checked by moving a color misregistration detection sensor along an attachment position candidate line that is defined in advance in a direction perpendicular to the rotational direction of an endless-belt-shaped transfer body. A specific attachment position on the sensor attachment position candidate line, at which color misregistration of the color image at a side edge portion of the transfer body becomes equal to the maximum value of color misregistration at a portion except the side edge portion, is found. The sensor is fixed at a position that satisfies the specific attachment position and opposes the color image formation surface of the transfer body. Accordingly, the image forming apparatus is controlled to correct color overlay on the basis of the detection signal of the color image by the sensor.

Abstract: The present invention relates to a print head (3) including an illuminator (5) for emitting light in a line extending in a primary scanning direction, a liquid crystal shutter (6) for selecting whether or not light traveling from the illuminator (5) is allowed to pass, and a light emitting portion (323) for emitting light traveling from the liquid crystal shutter (6) toward a photosensitive recording medium (22). The liquid crystal shutter (6) includes a plurality of individual shutter portions aligned in the primary scanning direction, for example. Preferably, each of the shutter portions is capable of individually selecting whether or not the light traveling from the illuminator (5) is allowed to pass.

Abstract: A scanning lens for an optical scanner includes a specific adjusting axis and a curved surface. The specific adjusting axis makes a rotating center of the scanning lens and center of the curved surface. The scanning lens is disposed on a holding member having a receiving surface, so that the curved surface is in contact with the receiving surface. A position of the scanning lens is adjusted by a rotating mechanism that rotates the scanning lens.

Abstract: There is provided an image forming apparatus which is capable of reducing a period of time required for obtaining an image output, in the case of changing the image forming operation from a monochromatic image formation to a color image formation during execution of the image forming operation. A plurality of image forming units form images and overlap images the formed images onto a transfer material. A preparation for image formation is started in a first mode in which image formation is carried out by the plurality of image forming units while image formation is being carried out in a second mode in which image formation is carried out by at least one of the image forming units. The image formation is carried out in the first mode after the image formation in the second mode is completed.

Abstract: The invention relates to an apparatus for printing a multibit per pixel image (10) from a halftone binary digital bitmap having pixels having a multibit per pixel image memory for receiving the multibit per pixel image; a lookup table (16) external to the memory disposed in a programmable gate array (18) for converting the multibit per pixel image to a base duty cycle (20) wherein the base duty cycle is disposed in the programmable gate array and is adapted for creating a modulated drive signal (22) from the base duty cycle to modulate an exposure (24) for each pixel in the multibit per pixel image; and a printer (28) adapted for using the modulated exposure to print an image, having a dpi greater than 1400, further comprising a drum (32) capable of spinning, and an encoder (34) disposed on the drum for providing a home signal (36) and a pixel rate (38).

Abstract: A printing apparatus (100) for printing digital images onto a photosensitive medium (140) employing, for exposure energy, a light source (20) that uses various arrays of LEDs (32). The printing apparatus (100) may form the print image using sequential modulation, one color at a time, or by applying all colors simultaneously. Arrangements of discrete LEDs (32) may include high-intensity devices configured with collector cones (41) arranged as a multicone structure (141), with parabolic reflectors (65), or collimating lenses (36). Large area LEDs (46) may alternately be used, arranged on an angled mounting surface (64), for example.

Abstract: A liquid crystal display unit has a transmissive liquid crystal plate having a number of pixels arranged on a two-dimensional basis, on which an image is formed, and a light source unit emitting beams of light of a plurality of luminescent colors for irradiating said liquid crystal plate from back. An interface circuit receives an image signal representative of a color image to sequentially form on said liquid crystal plate a plurality of separation images in which the color image is separated in association with the plurality of luminescent colors of said light source unit. The interface circuit causes said light source unit to flash with a luminescent color associated with a separation image formed on said liquid crystal plate in synchronism with a sequential formation of the separation images onto said liquid crystal plate. Beams of light emanated from the light source unit and transmitted through the liquid crystal plate reproduce an image.

Abstract: An object of the present invention is to provide a scanning optical system capable of reducing the number of its components and its size with a simple construction, and an image forming apparatus using the scanning optical system. In a specific scanning optical system, a plurality of light beams emitted from a plurality of light source units are deflected and scanned by a plurality of different deflecting facets of a common optical deflecting unit, and a plurality of scanned surfaces are scanned with the light beams deflected and scanned by the different deflecting facets, respectively.

Abstract: A method for repositioning a mark on a belt after an image on paper registration process, which includes printing a test pattern, measuring at least one test pattern parameter, detecting a mark on a belt and detecting at least one imaging error associated therewith, using the at least one test pattern parameter and the at least one imaging error to determine the lateral distance required to shift a particular image to a desired location on the belt and shifting the image to the desired location.

Abstract: A color shift correcting method for correcting a color shift due to misregistration of images in different colors, where a multi-color image is formed by developing latent one-color images written onto respective image carriers by an optical writing device, and directly or indirectly transferring developed one-color images onto a movable element, said method comprising the step of:

Abstract: Microarea light-emitting diodes, which have no variation in light output power the like due to mode-hopping, are used and changes in properties such as light output and the like due to generated heat are prevented. Pulses having a constant period and a substantially constant power are used, a number of the pulses within a period for forming an image corresponding to one pixel is determined on the basis of image data, and light beams emitted from the microarea light-emitting diodes are modulated by pulse signals including the determined pulses.

Abstract: An apparatus and method for applying dot-gain (110) compensation to halftone bitmap files used in printing a digital halftone image. Dot-gain is added by thresholding (250) the output of a convolution of the original bitmap image with a spatial filter (200). Averaging (220) is performed to specify the level of the threshold to be applied. The level of dot-gain applied is a function of the threshold level.

Abstract: In this invention, the relationship between the attachment position of a sensor and the formation positional shift of a color image is checked by moving a color misregistration detection sensor along an attachment position candidate line that is defined in advance in a direction perpendicular to the rotational direction of an endless-belt-shaped transfer body. A specific attachment position on the sensor attachment position candidate line, at which color misregistration of the color image at a side edge portion of the transfer body becomes equal to the maximum value of color misregistration at a portion except the side edge portion, is found. The sensor is fixed at a position that satisfies the specific attachment position and opposes the color image formation surface of the transfer body. Accordingly, the image forming apparatus is controlled to correct color overlay on the basis of the detection signal of the color image by the sensor.

Abstract: An image forming apparatus, which includes a plurality of image forming portions transferring a yellow image, a magenta image, a cyan image, and a black image formed on a plurality of photoconductor drums to a sheet conveyed on a conveying belt, a marking unit forming marks on the conveying belt, a detecting unit detecting the marks with three or more sensors aligned in a direction normal to a direction in which the sheet is conveyed, a calculating unit calculating an amount of color misalignment in accordance with results detected by the detecting unit, and a correcting unit correcting the color misalignment in accordance with the calculated amount of color misalignment, wherein the calculating unit calculates an amount of skew difference in accordance with results detected by two sensors among the three or more sensors, wherein one sensor of the two sensors is disposed on one end of the three or more sensors and the other sensor of the two sensors is disposed on the other end of the three or more sensors, w

Abstract: An image forming apparatus includes: a pattern generator for generating pattern data for recording a set of test patterns at respective specified positions thereof on the recording sheet; a positional deviation detector for detecting a positional deviation at each characteristic point included in the set of test patterns generated by the pattern generator, in the image data read from the recording sheet on which the image containing the set of test patterns has been formed, by comparing with a position of the proper output at each characteristic point; and a deviation correcting device for calculating operational values for a correction of each pixel with reference to the respective positional deviations of the characteristic points detected by the positional deviation detector and for carrying out a processing to eliminate the positional deviation of each pixel at the time of image formation by using the operational values.

Abstract: The present invention is directed to a method and apparatus for exposing photosensitive material to form high quality continuous tone and/or color images thereon. The preferred apparatus includes an imaging head comprised of a plurality of red light sources, a plurality of green light sources, and a plurality of blue light sources. The light produced by said green light sources is passed through a first filter having a narrow spectral transmission characteristic in the green spectral range. Similarly, the light produced by said blue light sources is passed through a second filter having a narrow spectral transmission characteristic in the blue spectral range.

Abstract: An optical system for an image forming apparatus which a first light source for selectably emitting a plurality of image forming light beams based upon control signals and a second light source for emitting image forming light beams of a number of less than that of said first light source. The first light source of the optical system selectably emitting multiple light beams and a single beam, e.g. selectably emits two beams and a single beam.

Abstract: Image carriers are arranged so as to satisfy an expression; −Ts/2<t1+t2−t3−nTp<Ts/2. “Ts” is a time period of scanning performed by each of scanning surfaces of a rotary polygon mirror. “Tp” is a time period of one rotation of the polygon mirror. “t1” is a time period required for a first image formed on a first image carrier among the image carriers is transferred to the transferred object at a first transferring position. “t2” is a time period required for the first image is traveled from the first transferring position to a second transferring position at which a second image formed on a second image carrier adjacent to the first image carrier at a downstream of the transporting path is transferred to the transferred object. “t3” is a time period required for the second image formed on the second image carrier is transferred to the transferred object at the second transferring position.

Abstract: A paper-feed roller and a fabrication method thereof in an office automation machine, such as a photocopier, a printer, and a facsimile machine, etc, includes forming a plastic roller along a general stainless shaft by a molding and forming a ceramic coating layer on a surface of the plastic roller. Accordingly, the paper-feed roller is capable of providing an economical effect in a fabrication cost and preventing a slipping of paper or a paper jam that is caused by a heat distortion and an abrasion occurring on a surface of a long time operated roller.

Abstract: An image forming apparatus is provided with photosensitive drums for forming latent images by irradiation of light reflected by a polygon mirror and a fixing device for fixing toner images corresponding to the latent images on a sheet material. Deterioration of an image to be formed is prevented if reflective surfaces of a reflective polyhedron are thinned out in reducing a process speed of image formation. This apparatus is further provided with a control unit for, if the number of surfaces of the polygon mirror is m (where m is an integer of three or more), performing a control for selecting n such that m/(n+1) is not an integer as a relation between m and n and performing a control for making n surfaces unused as a reflective surface of light among continuous n+1 surfaces of the reflective polyhedron in decelerating the image forming process.

Abstract: A light emitting element array is provided with a plurality of light emitting diodes arranged in a row, field-effect transistors connected in series with the respective light emitting diodes, shift registers for individually turning the respective field-effect transistors on by individually supplying drive signals to gates of the respective field-effect transistors, and an emission controller for driving the light emitting diodes by supplying the emission signals, whose levels are so differed as to correspond to the respective light emitting diodes, to the light emitting diodes connected with the field-effect transistors when these field-effect transistors are individually turned on.

Abstract: A laser beam display includes at least a first and second plurality of laser beam sources, each of which may preferably be an array of semiconductor lasers, providing a plurality of laser beams in an optical path so as to reflect off of reflective facets of a movable reflector and illuminate a display screen. In a color display, each column of the laser array corresponds to a separate primary color. The separate rows of each array correspond to independently activated but simultaneously driven scan lines to be illuminated by the laser beam scanning apparatus. The plural laser beam arrays subdivide the width of the screen into smaller scan segments to increase the scanning angle or increase the horizontal scanning speed of the apparatus. Tilted facets illuminate different vertical sections of the screen with the laser beams as the reflector rotates. A scan format employing simultaneously illuminated diagonal scan tiles provides optimal use of the plural laser beam arrays.

Abstract: At least one layer of cascading material overlying an EL lamp converts the light emitted by the EL lamp into infrared light. The EL lamp is supported within in a container transparent to at least infrared light, along with at least one battery and an inverter to provide power for the lamp in portable applications. The lamp is rolled to form a cylinder and fits within the inside diameter of the container. The lamp can be turned on or off by means of a switch interrupting current from a battery or to the lamp.

Abstract: In order to obtain a visually high quality image with excellent sharpness using a silver halide photosensitive material, it is necessary to reduce the ratio of EL light in the light output from a GaN based laser diode to 20% or less. For example, when the light intensity measured on a sheet of photosensitive paper is 0.05 mW, the thickness of a waveguide is 3 nm and the width of the waveguide is 3 &mgr;m, this condition is satisfied with a length of a resonator being 1 mm or less. In other words, a waveguide width W1 and a resonator length L are set such that the product of the waveguide width W1 and the resonator length L (W1·L) becomes 0.003 mm2 or less. This reduces the output ratio of the EL light, and a high quality image with excellent sharpness can be obtained when a silver halide photosensitive material is exposed.

Abstract: The present invention has an object to provide a highly accurate optical scanner of a simple construction which permits reduction of jitter caused by a division error of the deflection surface of a polygonal deflector, and to provide a color image forming apparatus using the same. The optical scanner of the invention comprises a plurality of scanning units each having a polygonal deflector onto which a flux emitted from a light source is directed, and a scanning optical system which forms the flux reflection-deflected by the polygonal deflector into spots on a surface to be scanned. In the optical scanner of the invention, two or more scanning units commonly use a single polygonal deflector.

Abstract: An image forming apparatus including an apparatus body, a single vertical stay disposed between optical writing devices and image forming cartridges and extending from a top wall to a bottom wall of the apparatus body, a plurality of horizontal stays disposed at least between consecutive image forming cartridges, and being attached to the single vertical stay, and a plurality of structural members disposed at least between consecutive image forming devices and being attached to the vertical stay. Further, the horizontal stays, the single vertical stay, the structural members and the apparatus body comprise a single structural body.

Abstract: An intermediate belt made of an endless belt is provided by 45 degrees inclined horizontally and looped over two rollers at both its ends, and four photosensitive drums are provided in contact with the top surface of this intermediate belt. A reflection mirror is provided over each photosensitive drum, and a single polygon mirror is provided on almost the same level as these reflection mirrors. The polygon mirror is provided on the side of the reflection mirror of which optical path to the corresponding photosensitive drum is the longest so that the optical path lengths from the polygon mirror to the respective photosensitive drums are equal to each other.

Abstract: Image carriers are arranged so as to satisfy an expression; −Ts/2 <t1 +t2−t3−nTp<Ts/2. “Ts” is a time period of scanning performed by each of scanning surfaces of a rotary polygon mirror. “Tp” is a time period of one rotation of the polygon mirror. “t1” is a time period required for a first image formed on a first image carrier among the image carriers is transferred to the transferred object at a first transferring position “t2” is a time period required for the first image is traveled from the first transferring position to a second transferring position at which a second image formed on a second image carrier adjacent to the first image carrier at a downstream of the transporting path is transferred to the transferred object. “t3” is a time period required for the second image formed on the second image carrier is transferred to the transferred object at the second transferring position.

Abstract: A two level image writer (10) for forming an image from digital data onto a photosensitive medium comprising an illumination system on a first level for providing incident light beams. The illumination system comprising a first source (20) for emitting a first polarized light beam having a first color; a second source (22) for emitting a second polarized light beam having a second color; and a third source (26) for emitting a third polarized light beam having a third color. A fold mirrors directs each beam to a second level and three polarizing beamsplitters (73, 75, 77) on the second level receive the polarized beams from the fold mirrors. Each polarizing beamsplitter isolates polarization states of each of the first, second, and third polarized light beam.

Abstract: An optical system for an image forming apparatus which a first light source for selectably emitting a plurality of image forming light beams based upon control signals and a second light source for emitting image forming light beams of a number of less than that of said first light source. The first light source of the optical system selectably emitting multiple light beams and a single beam, e.g. selectably emits two beams and a single beam.

Abstract: An optical scanner having excellent optical performance and guiding a light beam from one curved mirror directly to a photoconductive drum without requiring a reflecting mirror. The optical scanner includes: a light source unit (1); an optical deflector (5) for deflecting a light beam from the light source unit so as to cause scanning; a first image formation optical system (2, 3) for forming a line image on a deflection surface of the optical deflector, which is disposed between the light source unit and the optical deflector; and a second image formation optical system (7) composed of one curved mirror, which is disposed between the optical deflector and a surface (8) to be scanned.

Abstract: An image forming apparatus, includes an image forming unit including an image bearing member, a beam generating unit for generating a plurality of light beams and an optical scan system for scanning the image bearing member with the plurality of light beams to write an image, a beam detecting unit for detecting the plurality of light beams scanning the image bearing member at predetermined positions and obtaining a plurality of beam detection signals, a clock generating unit for generating a single clock signal, a controller for controlling the frequency of the single clock signal and a synchronization circuit for controlling the phase of the single clock signal in accordance with the plurality of beam detection signals obtained by the beam detecting unit, and generating a plurality of control clocks, wherein the plurality of beams are generated in accordance with the plurality of control clocks.